Originally Posted by Jeremy_Clark:
“Will the missing episodes ever be found?, you would have thought that the BBC would have made copies of all the episodes before they were sent out, or had a list of countries that the episodes were sent to.”
Will they be found? No - the vast majority of what's missing will remain lost forever. Some of the rumours doing the rounds of 70, 80, 90+ being found are utter, utter nonsense. There'll be a few more back, sure, but people expecting much more than a couple of dozen more back max - EVER - are deluding themselves. Think you're going to be watching 40 missing episodes in a couple of years courtesy of Phil Morris? Think again.
And, yes, there is info about which country bought what and when, but it is far from complete. The fact that copies were sent on to other countries (bicycling) just complicates the issue. As well as that, some countries returned stuff they were finished with; some destroyed it; and some kept it (despite the fact they weren't allowed to). And even if they kept it initially, do they still have it? So saying, "Such-and-such an episode must exist in country x," is a rather inexact science.
At the time each episode was sold abroad a master 16mm telerecording negative (at least) would have existed at BBC Enterprises. They were not sending "the last copy" abroad. All episodes (except "Feast of Steven") existed at BBC Enterprises in early 1972. These were junked from then until 1978.
In any case, it was not Enterprises business to maintain the BBC's archive of programming - if the BBC required an archive of old Who (or, indeed, anything else), Enterprises was not the place for it. The BBC had decided that very little of their old programming was required in the long term, so most of it went. Swathes of it until the 1950s and beyond was never recorded as it went out in the first place; if they needed a repeat, they performed it all over again.
The "master" copies of most Who episodes were the original tapes - these were separate from the Enterprises copies (above). All these survived until March 1967, but all the b/w episodes were wiped/junked between then and late 1974. However, for a few, the "master" recording is a 35mm film telerecording (rather than a tape) and most (not all) of these survive to date. "Wheel In Space" 6 is one of those, for example; the film that survives now is the same film it was transmitted from in 1968.
So, to summerise, and encapsulate.... all episodes survived at the BBC in some way or another until sometime in 1972 except "Feast of Steven" which went in August 1967.